Fix error
Rich interface example Rational
Update sbt
Add stackable modification sample
Add some file
Merge remote-tracking branch 'remotes/tanacasino/master'

Conflicts:
	src/main/scala/com/github/tanacasino/btree/BTree.scala
	src/main/scala/com/github/tanacasino/implicits/ImplicitAdder.scala
	src/main/scala/com/github/tanacasino/rational/Rational.scala
	src/main/scala/com/github/tanacasino/self/SelfTypes.scala
	src/main/scala/com/github/tanacasino/types/package.scala
	src/test/scala/com/github/tanacasino/rational/RationalSpec.scala
	src/test/scala/com/github/tanacasino/stackable/IntQueueSpec.scala